It is well known in the art to insulate buildings and machinery such as refrigerators and dishwashers and other appliances using various types of insulating materials including mineral fibers such as fibrous glass wool. Such insulation acts as a thermal barrier to heat, and may also act as an acoustic insulation against the transmission of sound.
Prior art glass wool blankets are generally formed with a well-defined shape. They often include a binder, such as a phenolic resin, added to the glass wool subsequent to the fiberizing process. The resultant insulating material has sufficient strength and rigidity to be employed as insulating blankets in walls, floors and ceilings.
However, prior art glass wool blankets, due to their use of primarily short fibers, binders, and general inability to recover from a compressed state to a shape other than their well-defined uncompressed state have limited ability to conform to the insulation cavities of a building into which they are installed. That is, building construction inevitably contains abnormal voids, for example, spaces created between floor, wall, and ceiling joists, as a part of the framing construction or non-uniformly shaped barriers such as electrical wiring, boxes and plumbing. Existing insulation blankets, being generally composed of primarily short fibers and substantially well defined shape, are unable to stretch and conform to and fill these abnormal voids. As a result, the effectiveness of the insulation is diminished when gaps and abnormal voids are present. Alternatively, the installer must cut the insulation to fit into the voids, increasing the time required to do the project. These gaps also reduce the insulation's effectiveness.
A further problem is presented by the use of conventional mineral fiber insulation material is the binder material which must necessarily be added to the fibers to provide product structural integrity. Binder provides bonding at the fiber to fiber intersections in the insulation blanket lattice. However, binders are expensive and have several environmental drawbacks. As most binders include organic compounds, great pains must be taken to process effluent from the production process to ameliorate any possible negative environmental impact. Further, the binder must be cured with an oven using additional energy and creating additional environmental cleanup costs.
Non-wool insulation products, such as loose fill, are also known. These loose fill products are conformable in the sense that they have no preordained shape. Loose fill is merely individual groups or nodules of insulation fibers. The insulation is generally installed by blowing into the area to be insulated. However, the insulation is difficult to handle, requires special equipment to install and due to its installation technique and loose nature, loose fill insulation can leave gaps and voids when blown into the cavity. These gaps and voids may be difficult to detect, since the vertical surfaces of the cavity (i.e., the inner and outer surfaces of a building wall) must be necessarily installed prior to filling the cavity with the loose fill material. Further, in contrast to an insulation batt, loose fill insulation cannot be handled as a unit.
Recently, binderless wool insulation products have been developed. U.S. Pat. No. 5,277,955 to Schelhorn et al. discloses a binderless insulation assembly. The insulation assembly comprises a mineral fiber batt, such as glass fibers, enclosed within an exterior plastic covering. Binder is not required. Adhesive is used to hold the plastic cover to the fiber batt. The insulation assembly of Schelhorn et al. is substantially fully expanded (uncompressed) prior to being installed into the voids or insulation cavities in construction spaces. Thus an installer must carefully cut and tuck the insulating material about any obstructions in the cavity into which the insulation assembly of Schelhorn et al. is being installed, being careful that the insulating material fully fills the cavity, in a manner similar to conventional glass fiber batts having binders.
U.S. Pat. No. 5,508,079 to Grant et al. discloses another binderless insulation assembly. The insulation assembly comprises a mineral fiber batt, such as glass fibers, which are substantially long and preferably irregularly shaped. The batt may be enclosed within an exterior plastic covering. Binder is not required. A layer of adhesive or other means for restricting movement holds the plastic cover to the fiber batt, allowing the insulation assembly to be installed vertically in walls, for example. The insulation assembly of the Grant et al. patent is compressed for packaging and shipment. When removed from the packaging, the batt begins to recover (expand from the compressed state). The insulation assembly is then installed into a construction cavity, continuing recovery due to handling associated with installation. As the insulation assembly continues to recover, it conforms to the cavity within which the insulation assembly is installed.
Another form of insulation assembly is shown in U.S. Pat. No. 4,726,974 to Nowobilski et al. The insulation assembly is an vacuum-sealed insulation panel comprising a compressed fiberglass substrate. The insulation assembly relies on the vacuum of the bag to maintain the insulating properties of the insulation assembly, which may be used, for example in about cryogenic equipment as a heat insulation panel. The insulation assembly of the Nowobilski et al. reference does not expand to conform to a cavity in which it is installed. Accordingly, the insulation assembly of the Nowobilski et al. reference is inappropriate for use in such applications as insulating between the studs of a building wall which contains abnormal voids created by such obstructions as electrical and plumbing connections.
Another form of insulation assembly is shown in U.S. Pat. No. 4,669,632 to Kawasaki et al. The insulation assembly is an evacuated bag containing a heat insulation material such as glass fibers. The insulation assembly relies on the vacuum of the bag to maintain the insulating properties of the insulation assembly, which may be used, for example in refrigerators as a heat insulation panel. The insulation assembly of the Kawasaki et al. reference is flexible but, like the Nowobilski et al. reference, does not expand to conform to a cavity in which it is installed. Accordingly, the insulation assembly of the Kawasaki et al. reference is inappropriate for use in such applications as insulating between the studs of a building wall which contains abnormal voids created by such obstructions as electrical and plumbing connections.
The need remains for an insulation assembly which conforms to abnormal voids in building spaces, is relatively easy and quick to install to minimize installation time and labor costs, and does not have the drawbacks of loose fill insulation. The need also remains for a method for installing such an insulation assembly in a relatively easy and efficient manner.